This invention relates to fluid displacement apparatus, and in particular, to fluid compressor units of the scroll type.
Scroll type apparatus has been well known in the prior art as disclosed in, for example, U.S. Pat. Nos. 801,182, 3,884,599, 3,924,977, 3,994,633, 3,994,635, and 3,994,636, each of which discloses two scroll members having an end plate and a spiroidal or involute spiral element. These scroll members are maintained angularly and radially offset so that both spiral elements interfit so as to maintain a plurality of line contacts between the spiral curved surfaces to thereby seal off and define at least one fluid pocket. The relative orbital motion of the scroll members shifts the line contact along the spiral curved surfaces and, therefore, the fluid pocket changes in volume. The volume of the fluid pocket increases or decreases dependent on the direction of the orbital motion. Therefore, scroll-type apparatus is applicable to compress, expand or pump fluids.
In comparison with conventional compressors of the piston type, a scroll type compressor has certain advantages, such as a lesser number of parts, continuous compression of fluid and others.
However, in order to increase compressive capacity and compression ratio, it is required that the number of turns of each spiral element be increased. This means that the diameter of the compressor unit is also increased.